Hasegawa J, et al. - Given that kidney biopsy is a gold standard for diagnosis of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), researchers assessed if vasculitis can be detected from AAV patients with minor urinary abnormalities. For this, 90 ANCA-positive patients undergoing kidney biopsy were evaluated retrospectively after being divided into two groups: group A (minor urinary abnormalities with both proteinuria <0.5 g/day and red blood cells ≤5 /high power field) and group B (major urinary abnormalities except group A). Findings suggested the utility of renal biopsy as a tool for histological diagnosis of ANCA-associated vasculitis in ANCA-positive patients with minor urinary abnormalities despite the lower rate of renal vasculitis to the total number of glomeruli sampled than patients with major abnormalities.